This invention relates to an injection molding apparatus, and more particularly to an injection molding apparatus which is provided with an injection molding machine and a permanent mold conveying path located close to the injection molding machine.
The molding operation of plastic products is classified into an injection cycle and a cooling cycle. The injection cycle is in general completed within as short as 10 seconds, while the cooling cycle takes more than 50 to 60 seconds. Accordingly, it is preferable that there be prepared a plurality of permanent molds, so that only injection cycle is attended upon by an injection machine, while the cooling cycle is carried out outside the injection machine, in an attempt to produce a great number of products within a limited period of time. To meet this end, there has been proposed a rotary type injecting machine, although this type of machine suffers from the following shortcomings. In other words, (i) this type of machine requires that a plurality of permanent molds be placed on a circular table, resulting in an increase in size of the aforesaid table, which in turn leads to an increase in the size of the injection apparatus; (ii) because of the failure to apply a sufficient tightening force to a permanent mold, there may not be achieved high-precision products; (iii) there is required an injection machine which is exclusively used for this type of injection, so that there results a complicated construction of an injection machine, and thus the machine is costly; (iv) Because of the failure to provide a sufficiently long stroke for a permanent mold, upon opening of the mold, there may not be achieved simple and positive opening and closing operations of permanent molds; and (v) For the above reason, there may not be achieved a simple device for opening and closing a permanent mold.